# Suboccipital Atretic Cephalocele as a Marker for Joubert-Plus Syndrome: An Extended Phenotype of the CPLANE1 Gene Mutation

## TL;DR

Two patients with suboccipital atretic cephalocele and Joubert-Plus syndrome are reported, highlighting a new link to CPLANE1 gene mutations.

## Contribution

Identifies suboccipital atretic cephalocele as a marker for Joubert-Plus syndrome linked to CPLANE1 gene mutations.

## Key findings

- Two patients with suboccipital atretic cephalocele were found to have Joubert-Plus syndrome.
- Genetic testing confirmed a pathogenic mutation in the CPLANE1 gene in both patients.
- The findings suggest suboccipital atretic cephalocele may indicate underlying brain malformations or genetic disorders.

## Abstract

Joubert syndrome (JS) is a rare neurological condition characterized by intellectual disability, hypotonia, and an abnormal breathing pattern. MRI brain frequently reveals the presence of the characteristic molar tooth sign. JS is usually inherited in an autosomal recessive manner, although sporadic cases have been reported. JS can present in association with other neurological conditions, such as Dandy-Walker syndrome; this is referred to as Joubert-Plus syndrome. In this report, we will present two patients who presented with a suboccipital swelling following a normal pregnancy and birth by elective Cesarean section at term. Both were found to be normocephalic with no facial dysmorphism and were referred for neurosurgical evaluation. MR imaging demonstrated the presence of Joubert-Plus syndrome. Genetic testing revealed a pathogenic mutation in the CPLANE1 gene. As shown in our two patients, JS can be associated with other central nervous system abnormalities such as the Dandy-Walker malformation in the mesencephalon or caudal fourth ventricle. In patients with atretic encephaloceles, the possibility of an underlying brain malformation or a genetic disorder should always be considered.